1. Field of the Invention
The present invention relates to a cosmetic preparation comprising ethylhexyl methoxycrylene and particulate inorganic photoprotective filter pigments.
2. Discussion of Background Information
The trend away from genteel pallor towards “healthy, sporty brown skin” has been unbroken for years. In order to achieve this, people subject their skin to solar radiation since this causes pigment formation in the sense of melanin formation. However, the ultraviolet radiation of sunlight also has a harmful effect on the skin. Besides the acute damage (sunburn), long term damage such as an increased risk of suffering from skin cancer, arises with excessive irradiation with light from the UVB range (wavelength: 280-320 nm). Moreover, the effect of too much UVB and UVA radiation (wavelength: 320-400 nm) is a weakening of the elastic and collagenous fibers of connective tissue. This leads to numerous phototoxic and photoallergic reactions, resulting in premature skin aging.
To protect the skin, a series of photoprotective filter substances has therefore been developed which can be used in cosmetic preparations. These UVA and UVB filters are summarized in most industrialized countries in the form of positive lists such as Annex 7 of the German Cosmetics Ordinance.
A particular form of UV photoprotective filter substances are the micropigments. The UV protective effect of the micropigments is based on the physical effects of reflection and light scattering. In cosmetic preparations, the micropigments used are almost exclusively inorganic micropigments made of titanium dioxide, zinc oxide or mixed oxides with, for example, iron oxides.
The advantages of micropigments as UV filter substance in cosmetic preparations are primarily that the pigments do not penetrate into the skin, in contrast to those which are present in dissolved or liquid form. The occurrence of allergic reactions is therefore excluded.
However, a disadvantage in the prior art is the fact that inorganic micropigments, particularly in relatively high concentrations, can only be incorporated into cosmetic preparations with poor stability. If the micropigments are provided with dispersion auxiliaries, moreover, the emulsifier system changes. The storage stability is then reduced. In this connection, oil-in-water emulsions (O/W emulsions) are particularly unstable.
Moreover, inorganic micropigments such as titanium dioxide and zinc oxide have the disadvantage of forming agglomerates in the preparation itself and also following application to the skin; these can be seen as unattractive, white residues. This phenomenon, called “whitening”, is not only visually unattractive, but reduces and alters the reflection and scattering behavior of these UV filters, as a result of which the UV protection of the preparation suffers. Also, this problem increases as the concentration of inorganic micropigments in the preparation increases.
In view of the foregoing, it would be desirable to have available cosmetic preparations (in particular O/W emulsions) into which inorganic photoprotective filter pigments (in particular titanium dioxide and zinc oxide) can be stably incorporated. In addition, the formulations, when applied to the skin, should have an absorption spectrum that is stable over a prolonged use period with appropriate UVA protection (Europe in accordance with Colipa, USA in accordance with FDA, UK Boots Star Ratio etc).